1. Field of the Invention
This invention pertains, in general, to door opening, closing, and latching hardware, and in particular, to a combination doorstop, holdopen, and shock absorber.
2. Description of the Prior Art
Devices for stopping the opening movement of a door hinged to a doorframe and/or for holding doors open at a predetermined position have application in many fields. For example, the automotive industry makes widespread use of such devices, as evidenced by U.S. Pat. No. 3,710,417 to Berman, et al, or that to Hollansworth in U.S. Pat. No. 2,893,050.
A similar device is illustrated in the Doorcheck and Holdopen of Semar in U.S. Pat. No. 2,779,050.
Similarly, the cabinet-making art frequently relies upon hinges which incorporate some means for stopping and/or holding a cabinet door at a predetermined open position. Examples of this art are to be found in, e.g., the disclosures of Tuerk in U.S. Pat. No. 313,457, Hoffman in U.S. Pat. No. 644,203, or to Gorgon, et al, U.S. Pat. No. 3,262,149.
One field to which this invention is particularly applicable is that of hinged appliance doors, e.g. refrigerator doors, and more particularly, to refrigerated display units such as are to be found in supermarkets and self-service stores. In this latter field, it is desirable to have a large, typically double-glazed door stopped and retained at an open position of about 90 degrees so that customers and/or stocking clerks can access the refrigerated contents of the cases conveniently for selection of purchases or for stocking. These doors typically are hinged separately and may incorporate an automatic return mechanism separately or within the hinge mechanism itself. Thus, it is desirable to have a mechanism which will retain the door in the opened position by a force of a predetermined amount at least equal to that exerted by the closing mechanism, which holdopen force can be easily overcome by the application of a greater manual, external closing force of a predetermined amount exerted on the door. Additionally, it is desirable that the doorstop and holdopen be capable of absorbing shock forces suddenly applied to the door, such as may be occasioned during the collision with the open door of passing vehicles, such as grocery carts, forklifts, etc., to avoid damage.
The object of the present invention is, therefore, the provision of a combination doorstop, holdopen, and shock absorber for a door hingably-attached to a door frame. It is a further object of the present invention to provide such a device that is simple and inexpensive to fabricate, but which is smooth and reliable in operation and able to withstand the rigors of hard use.